Method For The Destruction Of A Localized Mine

ABSTRACT

A method for the destruction of a localized mine, wherein an unmanned underwater vessel cooperates as a primary vessel ( 11 ) withy another unmanned remote-controlled underwater vessel acting as a secondary vessel ( 12 ) and which is provided with an explosive charge for explosion purposes. To reduce clearing costs compared to a method that uses a disposable vessel and to reduce clearing times compared to a method using a re-usable clearing vehicle, the primary and secondary vessels ( 11, 12 ) are used in an autonomously operating mode wherein the secondary vessel ( 12 ) is remotely controlled by the primary vessel ( 11 ). The tandem mode is effected as far as the mine ( 33 ) from the primary vessel ( 11 ) outwards by use of stored positional data on the localized mine ( 33 ) and on-board assisted navigation data; the mine ( 33 ) is relocalized using optical and/or optical sensors, and the secondary vessel ( 12 ) is positioned in relation to the mine ( 33 ) in a remote-controlled manner once the mine has been relocalized and the explosive charge is exploded by remote control.

The invention relates to a method for the destruction of a localizedmine, of the generic type defined in the precharacterizing clause ofclaim 1.

In the case of a known method for the detection and destruction of mines(EP 0 535 044 B1), an unmanned, remotely controlled underwater vehicle,a so-called ROV, as well as a remotely controlled search and minedestruction unit, which is equipped with an explosive charge for minedestruction, are used and are connected to one another via a glass fibercable. The ROV is connected via a further glass fiber cable to a surfacevessel which has a sonar system for detection and location of mines. Themine and search unit is also equipped with a transponder, acousticsensors such as a short-wave sonar, with optical sensors, such as a TVcamera with an illumination unit, and with sensors for measurement ofactual data for navigation, such as the direction of travel, the anglewith respect to the horizontal plane, the distance from the seabed andthe dive depth. The transponder corresponds with an acoustic positionsystem (APS), whose hydrophones are arranged on the ROV. The ROV has alaunching unit, a so-called launcher, which is used to deploy the searchand mine destruction unit. The search and mine destruction unit issteered by means of the APS by an operator, who is positioned in thesurface vessel, with respect to the sonar beam of the mine huntingsonar, which is directed at the mine. The search and mine destructionunit, whose transponder signals are displayed in the same way as themine echo signals on the display of the mine hunting sonar, is thencontrolled by the operator towards the mine, in the sonar beam of themine hunting sonar. The mine is examined by means of the TV camera, andthe search and mine destruction unit is moved by the operator to aposition with respect to the mine which is suitable for its destruction,and is then remotely detonated by the operator. The explosion of theexplosive charge of the search and mine destruction unit which, forexample, may be a shaped charge, initiates detonation of the mine, withthe search and mine destruction unit also being destroyed. With itsacoustic, optical and navigation sensors, the search and minedestruction unit is a relatively costly clearance appliance but, forcertain application, the time saving in mine destruction justifies thecosts incurred.

In applications in which the clearance times are less important incomparison to the procurement costs of the search and mine destructionunit, the search and mine destruction unit is not designed as adisposable vehicle with a weapon characteristic but as a reusableunderwater vehicle which simply places an explosive charge adjacent tothe mine and is recovered again by a surface vessel before detonation ofthe explosive charge and mine (Buschhorn and Schutz “Minenjagd—einemoderne Variante de Seeminenabwehr” [Mine hunting—a modern variant ofdefense against sea mines] Jahrbuch der Wehrtechnik [Defense technologyannual] 1976/77, pages 142-151). Once the search and mine destructionunit has returned to the surface vessel, the explosive charge isdetonated remotely from the surface vessel, for example by throwing ahand grenade into the water. The detonation of the explosive chargewhich this results in initiated via an acoustic fuze destroys the mineby sympathetic detonation of the mine as a result of the detonation ofthe explosive charge.

The invention is based on the object of specifying a method for minedestruction which minimizes the costs for the clearance appliance andresults in the clearance times being shortened considerably incomparison to methods which use a reusable search and mine destructionunit.

According to the invention, the object is achieved by the features inclaim 1.

The method according to the invention has the advantage that the use ofa primary vehicle and of a secondary vehicle which are both unmanned andhave their own propulsion system, as an autonomous tandem, that is tosay a tandem which is independent of a platform, allows the systemcomponents to be split in a cost-saving manner between the reusableprimary vehicle and the secondary vehicle, which is designed as adisposable vehicle and represents a weapon similar to a torpedo. Thisallows the costs which result from destruction of the secondary vehicleto be kept quite low. With the knowledge of the position data relatingto a mine which has already been localized and with the aid ofnavigation data from an on-board-based navigation device in the primaryvehicle, the tandem moves autonomously to the mine, while the primaryvehicle moves the secondary vehicle directly adjacent to the mine byremote control, and initiates the fuze for the explosive charge by meansof an appropriate detonation signal. Because it has its own propulsionsystem and its own steering apparatus, the secondary vehicle can bemoved by the primary vehicle to an optimum position for detonation ofthe mine, and can also be held in this position until the primaryvehicle has reached a safe separation distance from the mine. Thesetting of an optimum position of the secondary vehicle in turn allows asmall explosive charge to be used to reliably detonate the mine, so thatthe physical space which is required in the secondary vehicle foraccommodation of the explosive charge, as well as the total weight ofthe secondary vehicle, are reduced. This is of considerable importancefor mine clearance since a greater number of secondary vehicles can thenbe kept available for one primary vehicle, and can also be carried onthe platform. In comparison to a clearance appliance which places anexplosive charge adjacent to the mine, the secondary vehicle, whichrepresents a “mini-effector”, can be placed very much more accuratelyand can cause reliable destruction of the mine with a considerablysmaller amount of explosive.

Expedient embodiments of the method according to the invention togetherwith advantageous developments and refinements of the method arespecified in the further claims.

According to one advantageous embodiment of the invention, the primaryvehicle and secondary vehicle are connected to one another by means of acable via which steering signals as well as propulsion power for thesecondary vehicle are transmitted from the primary vehicle to thesecondary vehicle, and an electrical detonation signal for remoteinitiation of the explosive charge is also transmitted. While the tandemis traveling submerged to the mine, the cable length deployed betweenthe primary vehicle and the secondary vehicle is controlled such that itis continuously matched to the instantaneous distance between thevehicles. This prevents the possibility of the cable (in contrast to acable which is being unwound and is hanging loosely) from being able tosnag and tear on objects or bodies, or on external elements on thesecondary vehicle traveling in front of it, while approaching the mine.

According to one advantageous embodiment of the invention, thelocalization of the mine and the determination of the position datarelating to the localized mine, which is stored in the primary vehiclefor the mine destruction mission, are carried out from the platformdeploying the tandem, to be precise with the aid of a mine hunting sonarwhich is known per se.

A mine destruction system which is used with the method according to theinvention is specified in claim 13, and further refinements andimprovements of the mine destruction system are specified in claims 14to 17.

The invention will be described in more detail in the following textwith reference to one exemplary embodiment, which is illustrated in thedrawing, in which:

FIGS. 1 to 6 show successive instantaneous sections of the method fordestruction of a localized mine,

FIG. 7 shows a block diagram of a primary vehicle used for the method asshown in FIGS. 1 to 6, and

FIG. 8 shows a block diagram of a secondary vehicle used for the methodas shown in FIGS. 1 to 6.

In the case of the method for mine destruction as described in thefollowing text, a primary vehicle 11 and a secondary vehicle 12 areused, as can be seen in FIGS. 2 to 5. The vehicles 11, 12 are carried bya platform 10 which, for example, is a surface vessel, as illustrated inFIG. 1. Alternatively, platform 10 may also be a submarine, aninflatable boat or a helicopter. Each of the two vehicles 11,12 which isillustrated in the form of a block diagram in FIGS. 7 and 8 itself hasat least one propulsion motor 13 or 14, respectively, which ispreferably an electric motor, and a respective steering apparatus 15 or16 for actuation of control surfaces 17 and 18, respectively. Theprimary vehicle 11 also has an energy source 19 in the form of a fuelcell, a battery or a rechargeable battery, and a navigation device 20,and is equipped with acoustic sensors 21 and optical sensors 22 forunderwater use. A short-range sonar which is known per se is preferablyused as the acoustic sensor, and a TV camera with an illumination deviceis preferably used as the optical sensor. A cable drum 23 is alsoinstalled in the primary vehicle 11, and a connection cable 24 which canbe connected to the secondary vehicle 12 is wound up on this cable drum.All of the components are controlled by a control unit 25, which hasartificial intelligence 26 for processing of position data relating to alocalized mine, and navigation data from the navigation device 20. Amemory 27, which is accessed by the control unit 25, is provided forstorage of the position data relating to a mine which is intended to bedestroyed once it has been localized.

The secondary vehicle 12, which is designed as a disposable vehicle,represents a so-called mini-effector, which is essentially equipped onlywith an explosive charge 28 for mine destruction and with an associatedfuze 29. The propulsion power is supplied to the secondary vehicle 12from the energy source 19 in the primary vehicle 11 via the connectioncable 24. The connection cable 24 is also used for the transmission ofsteering signals to the steering apparatus 16 in the secondary vehicle12, and for transmission of an initiation signal, which activates thefuze 29. Control electronics 30 ensure that the individual componentsare actuated as a function of the signals which are transmitted via theconnection cable 24.

The method is carried out as follows, using these two vehicles 11, 12,which are used as an autonomously operating tandem during a minedestruction mission.

The specified mine clearance area is searched by the platform 10 bymeans of an actively locating sonar, a so-called mine hunting sonar 31.As is illustrated in FIG. 1, a mine 33 which is lying on the seabed 32,for example, is detected during this process, and is localized bydetermination of its position data in an earth-based coordinate system.If the localized mine 33 is intended to be destroyed, then the positiondata is stored in the memory 27 in the primary vehicle 11, and the twovehicles 11, 12, which are connected to one another by means of aconnection cable 24, are placed in the water (FIG. 2) by means of alaunching apparatus 34 (FIG. 1). The tandem which is formed by the twounderwater vehicles 11, 12 operates autonomously in that steeringsignals both for the primary vehicle 11 and for the secondary vehicle 12are generated in the primary vehicle 11 by means of the stored positiondata relating to the localized mine 33, and the navigation data in thenavigation device 20, and these steering signals are passed to thesteering apparatuses 15 and 16 in the two vehicles 11, 12. In this case,the data is processed using algorithms with the artificial intelligence26. During this process, the tandem first of all travels by the shortestpossible route in the direction of the seabed 32 (FIG. 2) in order thento approach the mine 33 along the seabed 32, but at a distance from it(FIG. 3). During this mission movement, the deployed cable lengthbetween the primary vehicle 11 and the secondary vehicle 12 iscontinuously matched (FIGS. 2 and 3) to the instantaneous distancebetween the vehicles 11, 12 by controlling the cable drum 23 in theprimary vehicle 11. There is therefore only a minimum amount of slack inthe deployed cable length of the connection cable 24, so that theconnecting piece of the connection cable 24 which is sliding in thewater cannot be snagged on objects in the water, or be caught onprojecting elements on the primary vehicle or secondary vehicle.

The mine 33 is relocalized by the primary vehicle 11 by means of theacoustic sensor 21 (FIG. 4), that is to say its position data isredetermined and is written to the memory 27, so that the control unit25 with the artificial intelligence 26 is now provided with improvedposition data relating to the mine 33 in order to produce the steeringsignals of the secondary vehicle 12, and the primary vehicle 11 can nowsteer the secondary vehicle 12 precisely to the mine 33. Once thesecondary vehicle 12 has reached the mine 33 (FIG. 5), a detonationsignal is generated in the primary vehicle 11 and is passed via theconnection cable 24 to the fuze 29 in the secondary vehicle 12, where itfires the explosive charge 28 which, for example, may be in the form ofa shaped charge, against the mine 33. On detonation of the mine 33, thesecondary vehicle 12 is destroyed, and the connection cable 24 is tornapart (FIG. 6). Once the secondary vehicle 12 has been positionedadjacent to the mine 33, a program routine is initiated in the controlunit 25 in the primary vehicle 11, causing the primary vehicle 11 toreturn to the platform 10, whose position data is likewise stored in thememory 27 in the primary vehicle 11, and the control unit 25 appliesappropriate steering signals for this purpose to the steering apparatus15 in the primary vehicle 11.

With some types of mine, it is necessary to visually inspect the mineaccurately, in order to place the secondary vehicle 12 optimallyadjacent to the mine 33. In this case, the tandem approaches the mine 33very closely so that all the details of the mine 33 can be seen from theprimary vehicle 11 by means of the illumination and the TV camera (FIG.4). The control unit 25 uses this optical data to generate appropriatesteering signals for the secondary vehicle 12, which are passed to thesecondary vehicle 12, in order to select an optimum position fordetonation against the mine 33. In this case, it is advantageous tostore data relating to the optical appearance of various mine types inthe primary vehicle, and to compare the data recorded by the TV camerawith the stored data. This allows the mine to be identified veryprecisely, and allows the best position of the secondary vehicle to beselected on the basis of the known characteristics of the identifiedmine. The primary vehicle 11 then moves to a safe distance away from themine 33 (FIG. 5), and causes the explosive charge 28 to explode, bymeans of a detonation signal (FIG. 6).

The invention is not restricted to the described exemplary embodiment.For example, the position data relating to the localized mine need notbe stored in the primary vehicle before the start of the missionmovement of the tandem. It can also be transmitted from the platform tothe primary vehicle by wire-free underwater communication while thetandem is traveling on its mission.

1. A method for the destruction of a localized mine (33), in which anunmanned underwater vehicle cooperates as a primary vehicle (11) with anunmanned, remotely controlled underwater vehicle as a secondary vehicle(12), which is equipped with an explosive charge (28), for detonation ofthe localized mine (33), characterized in that the two underwatervehicles (11, 12) are used as an autonomously operating tandem, in whichthe secondary vehicle (12) is remotely controlled from the primaryvehicle (11), in that the tandem is guided to the mine (33) from theprimary vehicle (11) by means of stored position data relating to thelocalized mine (33) and on-board-based navigation data, in that the mine(33) is relocalized from the primary vehicle (11) by means of acousticand/or optical sensors (21, 22), in that, once the mine (33) has beenrelocalized, the secondary vehicle (12) is positioned by remote controlfrom the primary vehicle adjacent to the mine (33), and in that theexplosive charge (28) is remotely detonated from the primary vehicle(11).
 2. The method as claimed in claim 1, characterized in that theprimary vehicle (11) additionally optically identifies the relocalizedmine (33) and uses stored mine data to optimize the position of thesecondary vehicle (12) adjacent to the mine (33).
 3. The method asclaimed in claim 1, characterized in that a program routine is carriedout in the primary vehicle (11) before remote detonation of theexplosive charge (28) and initiates a movement of the primary vehicle(11) away from the mine (33) corresponding to a predetermined safetyseparation.
 4. The method as claimed in claim 1, characterized in thatthe position data relating to the localized mine (33) is stored in theprimary vehicle (11) before the start of the mission for minedestruction.
 5. The method as claimed in claim 1, characterized in thatthe position data relating to the localized mine (33) is transmitted tothe primary vehicle (11) while carrying out the mine destructionmission.
 6. The method as claimed in claim 1, characterized in thatsteering signals for the primary and the secondary vehicle (11, 12) arecalculated in the primary vehicle (11) by means of artificialintelligence (26) from the position data relating to the localized mine(33) and from the on-board-based navigation data.
 7. The method asclaimed in claim 1, characterized in that the primary vehicle (11) andsecondary vehicle (12) are connected to one another by a connectioncable (34), and the steering signals are transmitted from the primaryvehicle (11) to the secondary vehicle (12) via the connection cable(24).
 8. The method as claimed in claim 7, characterized in thatpropulsion energy which is required by the secondary vehicle (12) istransmitted from the primary vehicle (11) via the connection cable (24).9. The method as claimed in claim 7, characterized in that a detonationsignal for remote initiation of the explosive charge (28) in thesecondary vehicle (12) is transmitted via the connection cable (24). 10.The method as claimed in claim 7, characterized in that, while moving intandem to the localized mine (33), the cable length of the connectioncable (24) which is deployed between the primary vehicle (11) and thesecondary vehicle (12) is controlled such that it is continuouslymatched to the instantaneous distance between the two vehicles (11, 12).11. The method as claimed in claim 1, characterized in that the primaryvehicle (11) and secondary vehicle (12) are carried jointly on aplatform (10), and are configured as a tandem after deployment from theplatform (10).
 12. The method as claimed in claim 1, characterized inthat the localization of the mine (33) and the determination of theposition data relating to the localized mine (33) are carried out bymeans of an actively locating sonar device which is arranged on theplatform (10).
 13. A mine destruction system having two unmannedunderwater vehicles which each have at least one propulsion motor (13,14) and a steering apparatus (15, 16) respectively, one of which isremotely controlled and has an explosive charge which can be detonatedremotely for mine destruction, and having acoustic and/or opticalsensors (21, 22) for underwater use, characterized in that theunderwater vehicles form a tandem which operates autonomously and iscomposed of a primary vehicle (11) and a secondary vehicle (12), in thatthe primary vehicle (11) has a memory (27) for storage of the positiondata relating to a localized mine (33), a navigation device (20) andcontrol electronics (25), and is equipped with the acoustic and/oroptical sensors (21, 22), and in that the secondary vehicle (12) isequipped with the explosive charge (28) and with a fuze (29) for remotedetonation of the explosive charge (28).
 14. The mine destruction systemas claimed in claim 13, characterized in that the primary vehicle (11)and the secondary vehicle (12) are connected to one another via aconnection cable (24), and in that the connection cable (24) is designedto transmit steering signals to the steering apparatus (16) for thesecondary vehicle (12), and/or to transmit electrical power from anenergy source (19), which is arranged in the primary vehicle (11), tothe secondary vehicle (12).
 15. The mine destruction system as claimedin claim 14, characterized in that the connection cable (24) can bewound up on a cable drum (23) which is installed in the primary vehicle(11), and in that the cable drum (23) can be controlled such that thedeployed length of the connection cable (24) from the cable drum (23) iscontinuously matched to the instantaneous distance between the primaryvehicle (11) and the secondary vehicle (12).
 16. The mine destructionsystem as claimed in claim 13, characterized in that the primary vehicle(11) has artificial intelligence (26) for processing of the positiondata relating to the mine (33), and of the navigation data from thenavigation device (20).
 17. The mine destruction system as claimed inclaim 13, characterized in that the acoustic sensors (21) have ashort-range sensor, and the optical sensors (22) have a TV camera withillumination.